MIT Professor: Put Cars On A Diet!

by Bertel Schmitt

Published: January 7th, 2012

The car industry is under pressure to improve fuel efficiency. It is not that they have been sitting on their thumbs. Automakers have achieved large increases in fuel efficiency through better technology in recent decades, says MIT economist Christopher Knittel.

The problem is:

“Most of that technological progress has gone into compensating for weight and horsepower.”

Between 1980 and 2006, the average gas mileage of vehicles sold in the United States increased by slightly more than 15 percent. During that time, the average curb weight increased 26 percent, their horsepower rose 107 percent. At the same time, the fuel economy of the engines actually increased by 60 percent between 1980 and 2006, Knittel shows in a new research paper, “Automobiles on Steroids,” published in the American Economic Review [$$$]. Most of those savings were used to buy more weight and horsepower.

If we would be driving cars of the same size and power that were typical in 1980, the country’s fleet of autos would have jumped from an average of about 23 mpg to roughly 37 mpg, well above the current average of around 27 mpg, Knittel says.

Currently, better fuel economy is mandated through complicated and sometimes skewed CAFE rules. Knittel thinks that compliance is easy: Maintain the rate of technological innovation experienced since 1980, and reduce the weight and horsepower of the average vehicle sold by 25 percent. Bingo, CAFE complied with.

If the country would shift back to the average weight and power common in 1980, a fleet-wide average of 52 mpg could be reached by 2020, Knittel calculates. However, Knittel does not think it will happen by itself.

The CAFE regulations will “end up reducing the cost of driving. If you force people to buy more fuel-efficient cars through CAFE standards, you actually get what’s called ‘rebound,’ and they drive more than they would have.”

Knittel’s solution?

“When it comes to climate change, leaving the market alone isn’t going to lead to the efficient outcome. The right starting point is a gas tax.”

(Hat tip to Dipl. Ing you-know-who)

#BertelSchmitt #CAFE #FuelEconomy #Knittel #MIT #Weight

Bertel Schmitt

Bertel Schmitt comes back to journalism after taking a 35 year break in advertising and marketing. He ran and owned advertising agencies in Duesseldorf, Germany, and New York City. Volkswagen A.G. was Bertel's most important corporate account. Schmitt's advertising and marketing career touched many corners of the industry with a special focus on automotive products and services. Since 2004, he lives in Japan and China with his wife <a href="http://www.tomokoandbertel.com"> Tomoko </a>. Bertel Schmitt is a founding board member of the <a href="http://www.offshoresuperseries.com"> Offshore Super Series </a>, an American offshore powerboat racing organization. He is co-owner of the racing team Typhoon.

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Another_pleb on Jan 08, 2012

What of agility? The ability to brake or swerve your way out of trouble on the road; a lighter car is bound to be more agile than a heavier one. Improved fuel economy would be a nice fringe benefit if cars were designed to be less likely to get involved in an accident in the first place. With improvements in rubber compounds, brake and suspension technology as well as advances in metallurgy and composite materials, it should be fairly simple for car companies to make a lighter, faster and more agile car that still fits the bill WRT passive safety and utility.

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- 95_SC on Jan 08, 2012
  
  O K, then ill ride my motorcycle...the agility argument has a point of diminishing returns too
  
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- Burgersandbeer on Jan 08, 2012
  
  People are more likely to use quick and agile cars to get themselves into trouble rather than out of it. Witness insurance rates for sporty cars vs trucks as proof.
  
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- Pch101 on Jan 08, 2012
  @burgersandbeer People are more likely to use quick and agile cars to get themselves into trouble rather than out of it. Pretty much. Enthusiasts refuse to believe this, but it's statistically accurate. And during emergency situations, most drivers respond by going hard for the brakes. This is true even among drivers who are trained to do otherwise. Fatality rates have been on the decline because cars crash much better than they used to. Airbags, seat belts and crush zones trump agility and driver training in a heartbeat.
  
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- DenverMike on Jan 08, 2012
  
  @Burgersandbeer There's no disputing sports car drivers are more likely do stupid things at the wheel BUT having the agility to better avoid accidents when OTHER people do stupid things is a whole other topic. Also a topic that no one keeps stats on. There are plenty thankful people out there that I was in a sports car and knew what to do with it when THEY ran a stop sign or didn't see me (driving at or under the speed limit) till I was right on top of them. I've heard people quote studies that say "Drivers with drivers training are more likely to crash..." but when you read the actual studies, they have more holes than swiss cheese!
  
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- Pch101 on Jan 08, 2012
  @burgersandbeer when you read the actual studies, they have more holes than swiss cheese! That's funny. When I provided you with an academic study to read, your responses to it made it clear that you weren't capable of comprehending its contents. You're not in much of a position to comment on their accuracy or lack thereof, either way.
  
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- DenverMike on Jan 09, 2012
  
  @Pch101 Getting you to produce it was like pulling teeth. It became pretty obvious why you stalled once I read it. Yeah I understood it but it's you that's misapplying its message to fit your agenda. No one but you was talking about high school 'drivers training'. Nor did it cover advanced drivers at the (amature)competition level. People that may posses an SCCA licence and or regulars at autoX events for instance. The study (and it was just one study that you could come up with) just covered folks that took a simple advanced/defensive driving class but never followed it up. IE, just enough to make themselves dangerous.
  
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- Another_pleb on Jan 09, 2012
  
  @mkirk Point taken about diminishing returns but I think you are creating something of a false dichotomy here. A large motorcycle like a Goldwing or a big Harley is probably not much safer for its rider if it gets crashed into than a small motorcycle like a Vespa. With motorcycles, the biggest factor WRT rider safety is protective clothing. Modern computer design and materials should make it easier to have a lighter car with the same size and crash-worthiness as a heavier one. I'm not advocating that all cars should be Lotuses just that their ordinary common or garden Ford has a few kgs shaved off here and there with intelligent use of available tech.
  
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Nrd515 on Jan 09, 2012

Too bad you can't legislate stupid out of people. Everyone screws up once in a while while driving, but let's be honest here, there are a lot of people driving badly out there. Almost 9 years ago to the day ago, I was involved in a bad wreck due to a 20 year old's stupidity, and if it hadn't been for the air bag and size of my vehicle, I would have been injured much more severely than I was. I've never been the same since that wreck, but I would have certainly been more severely injured if the 2000 GMC Sierra I was riding in was a 1985 GMC truck.

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